DE 44 36 397 B4 relates to a device for the aftertreatment of exhaust gases. The device comprises an exhaust manifold system, in which a reduction catalytic converter is arranged for reducing NOx constituents of the exhaust gas from the internal combustion engine. The device further comprises a metering device, comprising an electrically controlled metering valve for the metered introduction of a reducing agent into the flow of exhaust gas delivered to the catalytic converter, as a function of a value for the NOx content of the exhaust gas stored in the mapping for various operating parameters of the internal combustion and the catalytic converter. The valve for controlling the air feed is an electrically controlled control valve, which is arranged downstream of outlet aperture of the metering valve and the outlet aperture of which opens directly into the exhaust gas flow from the internal combustion engine. The control valve is accommodated by a body with a cooling medium flowing round it, so that the control valve is cooled.
US 2008/0236147 A1 discloses an injection system, which as part of the selective catalytic reduction on a motor vehicle is used for reducing NOx fractions in the exhaust gas. According to this solution the injection system comprises an injector, which is supplied with current via an electrical connection. Situated within the electrical connection is an electrical contact which is configured to receive a connector of a connection lead.
The subject matter of US 2010/0108020 A1 is a connection system for electrical leads which are laid in hazardous areas, such as, for example, in an area in which there is a risk of explosion, for example in the surroundings of an internal combustion engine. The connection system disclosed is suitable for the electrical connection of leads of various sensors and components. The connection system comprises a protective rubber sleeve and a cap, which is provided with an internal thread. Here the protective rubber sleeve serves as an electrical and thermal insulator and is compressed in the assembled state of the connection system.
DE 10 2009 060 065 A1 discloses a fluid line for urea-water solutions in NOx reduction devices which function on the selective catalytic reduction (SCR) principle. The fluid line is made from a thermoplastic vulcanizate. The thermoplastic vulcanizate has rubber-like characteristics and is also known as a thermoplastic elastomer. An outstanding characteristic of the thermoplastic vulcanizate is its high resistance to aggressive fluids and it possesses a very high flexibility and an outstanding pliability. According to DE 10 2009 060 065 A1 a fluid line produced from a thermoplastic vulcanizate is used for connecting tanks, pumps and injection nozzles or to accommodate couplings.
In metering modules, which are used as part of exhaust gas aftertreatment systems, use is made of injection valves which serve for urea metering. In order to get as close as possible to the exhaust gas flow with the valve tip of the injection valve, the valve fixture in these metering modules is actively cooled. This is done through a connection of the valve body to the coolant circuit of the vehicle. This ensures that, even when the valve is positioned close to the exhaust gas, in operation the valve tip temperature does not exceed 120° C. Where in a metering module a connection fitting, made of plastic (PA66) and affording contact with the supply feed for the automotive fluid/additive, runs outside the cooling element, it is exposed to the ambient temperature and in critical operating states, such as at high ambient temperatures, for example, may heat up in operation or in the event of heat soak.
In such cases a high heat input may pass via the plastic connection fitting into the O-ring situated under the former and serving for sealing purposes.